The present invention relates to a shift device with an over-shift lock for a multi-speed transmission for motor vehicles and, in particular, to a shift device having a shifting shaft which is rotated incrementally by way of a pivotable shifting element. The shifting element includes hook-shaped claws which, during the pivoting of the shifting element, rotate the shifting shaft by way of driver pins for engaging a next higher or a next lower transmission gear.
Shift devices of this type are frequently found in motorcycles or motorcycle-like vehicles having three or more wheels. They permit a sequential shifting operation; i.e., during each shifting operation, the next-higher or next-lower gear is engaged in the transmission.
German Patent document DE 196 17 988 C2 describes such a shift device. The known solution provides a pivotable shifting arm which is acted upon by a shifting lever operable, for example, by the driver's foot. A shifting element, which rotates a shifting shaft about a defined angle during the pivoting of the shifting arm, is linked to the shifting arm. For this purpose, the shifting element has hook-shaped claws which engage with driver pins arranged circularly around the axis of the shifting shaft. A shift drum with shift forks held in grooves is connected with the shifting shaft. During the rotation of the shifting shaft and, therefore, of the shift drum, the forks shift the gears in the vehicle transmission in a known manner.
In addition to the shifting element, in the case of the known construction, a locking element is linked to the shifting arm. The locking element moves synchronously with the shifting element. Bow-type elements, which are shaped out at the locking element, are used as stops for the driver pins of the shifting shaft, with the goal that, in the event of a shifting intention, the shifting shaft will rotate only by the predefined angular distance.
It is an object of the invention to limit the rotation of the shifting shaft, when shifting is intended, by use of simple devices in the case of a shift device of the above-mentioned type.
This and other objects are achieved by a shift device with an over-shift lock for a multi-speed transmission of a motor vehicle having a shifting shaft which is rotated incrementally by way of a pivotable shifting element, the shifting element including hook-shaped claws which, during the pivoting of the shifting element, rotate the shifting shaft by way of driver pins for engaging a next higher or a next lower transmission gear. The shifting element is designed in two parts. The first component, an activating element, is coupled with the shifting lever and transmits the intention to shift initiated by the shifting lever to the second component, which is a driver element with hook-shaped claws. The two components are springably displaceable with respect to one another along their longitudinal axis and have corresponding oblong holes. A shifting shaft penetrates both oblong holes. At the predefined end of a pivoting movement of the shifting element, the shifting shaft, the activating element and the driver element block one another so that an independent further turning of the shifting shaft caused by inertia is effectively prevented.
When the shifting lever is released, the shifting element will rotate back as a result of a restoring spring, and the contour of the oblong hole in the driver element will permit a release of the blockage. For this purpose, the upper longitudinal side of this oblong hole has the shape of a saddle roof. During the release, the driver element is forced downward by the driver pin assigned to it at that moment, while the shifting shaft moves along a roof inclination of the oblong hole.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.